Manufacture of tobacco sheet



Dec. 12, 1961 -H. B. MERRITT 3,012,562

MANUFACTURE OF TOBACCO SHEET Filed June 12, 1957 GRIND GRIND TOBACCOADHESIVE MIX GROUND TOBACCO AND ADHESIVE MELT ADHESIVE FORM SHEET HARDENADHESIVE CUT SHEET TO SIZE INVENTOR HENRY B. MERRITT ATTOR Y UnitedStates Patent 9 3,012,562 MANUFACTURE F TOBACCO SHEET Henry B. Merritt,Mamaroneek, N.Y., assignor to American Machine & Foundry Company, acorporation of New Jersey Filed June 12, 1957, Ser. No. 665,160 5Claims. (Cl. 131140) This invention relates to the manufacture oftobacco sheet. In particular the invention relates to a random mixtureof a major part of finely divided tobacco and a minor part ofthermoplastic adhesive.

Many proposals have been made for making tobacco sheet from finelydivided tobacco. All of these methods have relied upon the treatment ofan adhesive material with a solvent or liquid dispersing material whichis removed by evaporation from the tobacco sheet. Usually this materialhas been Water, but organic solvents have also been suggested for usewith thermoplastics such as cellulose acetate. Such liquid materialstend to harm the tobacco aroma or increase the cost of manufacture.

Heretofore mixtures of tobacco and adhesive have been dry mixed andformed into a sheet with the addition of moisture. However, all of thesesheets have been easily disrupted by excess water and have requiredelaborate evaporation procedures in order to adjust moisture content.

Therefore, it is an object of this invention to provide a method offorming tobacco sheet from a thermally softened adhesive, preferablywithout the use of liquids.

Another object of the invention is to provide a tobacco sheet whichincludes finely divided tobacco and a thermally softened adhesivematerial.

These and other objects are described more particularly in the followingaccount of the invention taken together with the accompanying drawingwhich shows a box type schematic flow sheet of a method of makingtobacco sheet according to the invention.

According to a preferred form of the invention as shown in the drawing,a minor proportion of thermoplastic adhesive powder is mixed with amajor propor tion of finely divided tobacco, preferably although notnecessarily in the absence of liquid, and the mixture is heated tosoften or fuse the plastic. The mix is formed into a sheet, cooled andcut to size. Fibers, fillers and plasticizers may be added to the drymix before the sheet is formed.

Heating of the plastic adhesive is advantageously done by dielectricheating although convection heating with hot gas is also useful. Whendielectric heating is used, the moisture content of the tobacco ispreferably about 25%. Heated rollers are also useful in forming thetobacco sheet.

Generally a very thin sheet is formed. A sheet between one and ten milsis useful but about four mils is preferable.

The adhesive may be cured and hardened, as by an included catalyst, orrefrigeration, and after a brushing to remove loose tobacco material,which may be reused, the sheet is rolled and cut to appropriate size.

The sheet is suitable for use in smoking articles such a cigars andcigarettes, both as shredded filler and as binder or wrapper.

The preferred adhesive for use with tobacco in this invention iscellulosic and particularly ethyl cellulose. Various cellulose baseesters and mixtures and copolymers thereof are also equally suitable.These include acetate, propionate and butyrate of cellulose.

Alkyl cellulose others such as ethyl cellulose are suitable,particularly when 50% or more of the hydroxyl radicals of cellulose havebeen replaced by alkoxy groups.

Non-cellulosic thermoplastic polymers such as olefins of thepolyethylene type and polyamides of the nylon type as well as vinyl andvinylidene resins such as polyvinyl alcohol are also suitable. Waxes mayalso be used. All of the adhesives may incorporate conventionalplasticizers.

Although some of the non-cellulosic materials burn poorly, they are usedin relatively small amounts and may be combined with conventional burncatalysts so that the sheet will, nevertheless, burn Well andundesirable odor is masked by the preponderant quantity of tobacco whichis preferably over by weight.

The following example illustrates the invention in a preferred form:

Example About grams of dry ethyl cellulose powder of about 50% ethoxycontent and of about 150 US. standard mesh size is mixed with about 1000grams of dry ground tobacco of similar size and of about 20% moisturecontent on a dry weight basis. The mixed powders are heated to about C.in an oven until an even temperature prevails throughout the mass andthe plastic polymer has become very soft. The hot dough-like mixture issqueezed through a series of hot rollers until a sheet about six milsthick is made. This sheet is then run through cold rollers and theresulting sheet is cut to useful size for shredding into a cigaretteblend. This is shown in the drawing.

What is claimed is: p

1. A method of making tobacco sheet comprising in combination the stepsof combining a major proportion by Weight of finely divided tobacco anda minor proportion by weight of thermoplastic adhesive, applying heat tothe tobacco and adhesive and forming the combination of tobacco andadhesive into a sheet.

2. A method of making tobacco sheet comprising in combination the stepsof mixing finely divided tobacco with finely divided thermoplasticadhesive to form an intimate mixture, heating said plastic adhesive tosoften the same, adhering tobacco thereto, extruding said mixture as atobacco sheet and hardening said plastic.

3. A method of making a tobacco product comprising heating athermoplastic material until it is soft and adhesive, adhering finelydivided tobacco thereto and thereafter cooling said adhesive material.

4. A method of making a tobacco product comprising shaping a mixture offinely divided tobacco and a thermally softened adhesive while saidadhesive is soft and thereafter allowing said adhesive to cool.

5. Amethod of making a tobacco sheet comprising in combination the stepsof combining a major-proportion by Weight of finely divided tobacco anda minor proportion by weight of thermoplastic adhesive rendered soft byheat, forming the composition of tobacco and hot, soft adhesive into asheet and thereafter cooling said sheet.

References Cited in the file of this patent UNITED STATES PATENTS 61,275Stayman Jan. 15, 1867 5, 64 Grunauer Feb. 16, 1932 4 ,549 Edmonds Jan.10, 1939 9,975 Moseley et a1. Feb. 2, 1943 .4 .877 Wells et al Jan. 6,1948 ,483,418 Kamlet Oct. 4, 1949 70 Sowa et a1. Oct. 25, 1949' 75Samfield et a1. May 10, 1955 83. Frankenburget a1. May 29, 1956

1. A METHOD OF MAKING TOBACCO SHEET COMPRISING IN COMBINATION THE STEPSOF COMBINING A MAJOR PROPORTION BY WEIGHT OF FINELY DIVIDED TOBACCO ANDA MINOR PROPORTION BY WEIGHT OF THERMOPLASTIC ADHESIVE, APPLYING HEAT TOTHE TOBACCO AND ADHESIVE AND FORMING THE COMBINATION OF TOBACCO ANDADHESIVE INTO A SHEET.